Pilocarpine in is an alkaloid having miotic and parasympathomimetic properties which is the basis of various pharmaceutical preparations and particularly ophthalmological preparations. Used as a miotic substance, it, for example, reduces the intraocular pressure in the eye. Pilocarpine is thus employed preferably in the treatment of glaucoma.
Production of pilocarpine is at the present time principally carried out by its extraction from the leaves of wild Pilocarpus. In point of fact, the production of pilocarpine by chemical or biochemical methods remains difficult and arduous. However, cultivation of Pilocarpus is long, difficult and at the present time not well developed. Indeed, Pilocarpus seeds only retain their power of germination for a very short time and plantlets grow particularly slowly.
U.S. Pat. No. 5059531 describes a process for the vegetative propagation of Pilocarpus plants. In this process, a suspension of undifferentiated Pilocarpus cells is subjected to hormone treatment which induces differentiation in vitro of cells into buds (or leaves). These buds are then subjected to hormone treatment which induces the formation of roots. Plantlets are thus obtained which will subsequently be cultivated in fields with the aim of harvesting the leaves. This process thus enables a large number of identical Pilocarpus plantlets to be obtained rapidly, but it does not resolve the disadvantages associated with their cultivation in the field.
U.S. Pat. No. 5,059,531 also describes the possibility of extracting pilocarpine directly from induced buds. However, this in vitro cultivation of buds has disadvantages. First of all, buds do not have the capacity to multiply as undifferentiated cells do, the biomass of the culture thus increasing solely due to the lengthening of buds. Cultivation is thus long and limited in volume. Secondly, the concentration of pilocarpine, in buds is less than that present in the plant by a factor of 10 and the quantity of pilocarpine that can be purified is thus also limited.